A rambling mind

Current affairs, cycling, Mallorca and lots more ravings of a rambling mind – also see https://www.briansutton.uk for more that gets my attention

Latest from the Blog

Solving log(x) = R(x-1) for a family of R values, with R up to 7

Implications of the R0 Reproduction Number in an unconstrained Delta variant environment

In my April 8th 2020 post about the R0 reproduction number and the use of SIR models to model the pandemic, I developed a chart which predicted the proportion of the population uninfected by the end of an unconstrained pandemic.

That chart allowed for an R0 up to 3, but the Delta variant that arrived in the UK a year later, in April 2021, has an R0 far higher than the original, possible 2.5 times as high, as much as R0=7, perhaps.

I have added to the scope of that previous post to develop a chart allowing R0 up to 7..

Repeated elements of the 164-compartment model flowchart with Uninfected, Vaccinated, double Vaccinated, Recovered and Deceased compartments for each group; and Incubation, Sick, Seriously Sick, and Better infective compartments per group, per variant and per vaccination status, with associated transition rates

“Freedom Day”, multiple vaccinations and the Delta variant

In this post, I run a development of my model which includes immunity waning (at a 150 day half-life), vaccine hesitancy by group, multiple vaccine inoculations (representing the typical two jabs required by most vaccines for best immunity) and also the possibility of vaccinated people not only to become infected, but also to pass on the virus even if not infected themselves.

Chart 318 for scenarios UK479 and UK465 with vaccinations and 2021 NPI relaxations up to June 21st with 4% and Aug 16th with 2% NPI effectiveness. v3 transmission k11 = 1, var_eff = 100%, fss and fmort as fort v1 and v2. Modelled 800 day outcomes to April 12th 2022 compared with reported active cases and deaths to June 4th. Serious cases for three variants.

Delta variant impact on June 21st easing – delay or reduce?

Having explored what pandemic advisers might be seeing and highlighting to decision-makers in Government, I run scenarios with different settings for the planned June 21st relaxation of lockdown, the last in the series of relaxations over the first half of 2021, following the January 3rd lockdown. These model scenarios show examples of what the relative consequences of the June 21st relaxation as planned, versus four other options:- cancellation of the June 21st step altogether, two different delays, of 28 and 56 days, and lastly a 50% reduction in the scope of the June 21st relaxation.

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